bug#36448: 26.2; doc string of `highlight-lines-matching-regexp'

[Eli Zaretskii]

> Date: Sun, 30 Jun 2019 13:40:10 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> This part of the doc string is not so good:
> 
>   Set face of all lines containing a match of REGEXP to FACE.
> 
> That's not what happens - "set" is the wrong verb here (face attributes
> are set, but not the displayed face as a whole).

Thanks, fixed.